Steel.



UNITED STATES PATENT OFFICE.

CHARLES HERBERT I-IALCOMB, OF NEW YORK, N. Y.

STEEL.

SPECIFICATION forming part of Letters Patent No. 722,504, dated March 10, 1903.

Application filed January 21, 1903. Serial No. 139,991. (No model.)

To all whom it may concern:

Be it known that I, CHARLES HERBERT HAL- COMB, a citizen of the United States, residing at New York city, in the county of New York and State of New York, have invented certain new and useful Improvements in High- Grade Steels; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to the manufacture of high-grade steel, particularly adapted for making tools used in working steel. Of late years the service demanded of such tools either for working harder or tougher steels or for working any steels faster has become much more severe, requiring a tougher and more enduring tool of a sufficiently high degree of hardness. Formerly where an increase in endurance and hardness was desired it was commonly produced by an increase in the percentage of carbon, sometimes nearly two per cent. or even a little more being added to the steel. In my experimentsI have found that in the severe Work referred to such a high degree of heat was developed that tools depending on carbon to any great extent for their hardness and endurance became too soft and useless for the purpose in question on account of the carbon-being more or less burned out.

My invention consists in the discovery that a steel of the necessary hardness, toughness, and endurance may be produced, which will not materially deteriorate under such high temperature,by considerably diminishing the amount of carbon in the steel and by adding thereto a large amount of molybdenum. The carbon should not be over 1.20 per cent., though I prefer to reduce it below one per cent., and of molybdenum not less than six per cent. nor more than about fifteen per cent. should be added. I have obtained excellent results with tools made of a steel containing about .60 per cent. of carbon and about ten per cent. of molybdenum. With my proportions of carbon and molybdenum even if a small amount of carbon be burned out it does not materially afiect the quality of the steel.

I have found that for certain purposes the quality of the steel may be improved by using a considerable amount of chromium in addition to the molybdenum and without much change in the amount of the latter. A small amount of chromium is of no advantage, and at least 2.5 per cent. but not over six per cent. must be added. I have also found that for some purposes a finer cutting edge may be obtained by using, preferably, with the chromium a small amount of silicon, at least .30 per cent. and not over 1.50 per cent. The silicon may be used without the chromium, if desired, the important feature of myinvention being the production of an alloy steel of the necessary hardness, toughness, and endurance by using with the small amount of carbon the large amount of molybdenum specified.

While my new alloy steel is particularly adapted for tools, I do not limit it thereto, but desire to protect it for all purposes for which it may prove useful.

If desired, manganese and nickel may be added to the composition, either with or without the chromium and silicon.

The molybdenum is generally obtained either as metallic molybdenum or as ferromolybdenum, and the necessary amount of either of those metals (or of both mixed) is added to the base material by usual methods to give the desired proportion of molybdenum in the finished product.

What I claim, and desire to secure by Letters Patent of the United States, is-

1. A high-grade steel containing less than 1.20 per cent. of carbon, and from six per cent. to fifteen per cent. of molybdenum.

2. A high-grade steel containing less than 1.20 per cent. of carbon, from six per cent. to fifteen per cent. of molybdenum and from 2.50 per cent. to six per cent. of chromium.

3. A high-grade steel containing less than 1.20 per cent. of carbon, from six per cent. to fifteen per cent. of molybdenum, from 2.50 per cent. to six per cent. of chromium and less than two per cent. of silicon.

In testimony whereof I afflx my signature in presence of two witnesses.

CHARLES HERBERT HALCOMB.

Witnesses:

ALFRED WILKINSON, M. B. SMITH. 

